Cementless Triathlon 5YR Follow-Up

Implant movement will be measured with model-based Radiostereometric Analysis (RSA) by registering the location of the tibial component during supine exams. Potential tibial component migration between 1 and 5 years post-operation will be measured in millimeters with the use of tibial bone markers.

Implant movement will be measured with model-based Radiostereometric Analysis (RSA) by registering the location of the femoral component during supine exams. Potential femoral component migration between 1 and 5 years post-operation will be measured in millimeters with the use of femoral bone markers.

Model-based Radiostereometric Analysis (RSA) will be used to register the location of the tibial and femoral components during supine and standing exams. Change in implant position will be measured in millimeters as maximum total point motion (MTPM) between the standing and supine RSA exams.

Weight-bearing computed tomography (CT) will be used to register the location of the tibial and femoral components during seated and standing exams. Change in implant position will be measured in millimeters as maximum total point motion (MTPM) between the seated and standing CT exams.

Weight-bearing computed tomography (CT) scans will be used to measure bone density as Hounsfield units in standardized volumes of interest below the pegs and keel of the tibial component.

Weight-bearing computed tomography (CT) texture analysis will be performed in standardized volumes of interest below the pegs and keel of the tibial component.

Participants will provide a stool sample. Microbial DNA will be extracted from the stool samples for 16s rRNA sequencing. Taxonomy will be assigned and functional annotation will be determined.

Patient reported outcome measure observing physical and mental health status of patient. There are 12 questions asking about health (excellent to poor), activity limitations (yes, limited a lot to no, not limited at all), problems with daily activities from physical or emotional health (yes or no), pain interfering with normal work (not at all to extremely), recent positive or negative feelings (all of the time to none of the time), and interference of physical or emotional problems with social activities (all of the time to none of the time). A higher score indicates better physical and mental health function.

Patient reported outcome measure observing physical symptoms following recent knee replacement surgery. Contains 24 questions asking about the amount of pain, stiffness, and activity difficulty (none to extreme). A higher score indicates greater pain, stiffness, and activity difficulty.

Patient reported outcome measure. Contains 5 sections measuring patient symptoms (none to severe), satisfaction (very satisfied to very dissatisfied), expectation (too high to too low), functional activities, and discretionary knee activities. Functional activities are split into walking and standing (with or without aids and the duration), standard activities (no bother to cannot do), and advanced activities (no bother to cannot do). Discretionary knee activities measure difficulty with the three most important activities for the patient (no bother to cannot do). Higher scores indicate greater patient outcomes.

Patient reported outcome measure observing activity level of patient. Contains a 10-level scale with 1 representing a patient who is inactive and dependent on others, to 10 representing a patient who regularly participates in impact sports. A higher score indicates a greater activity level.